Tesla and SpaceX CEO Elon Musk has made another apprehensive comment on the future of artificial intelligence development, saying the country with “[artificial intelligence] superiority most likely cause of WW3” on Twitter.

Musk, the most prominent critic of AI development, was responding to a comment by Russian President Vladimir Putin, who said the nation that leads in AI will be “leader of the world.”

The comment is just the latest from Musk, who has taken to Twitter previously to call on governments to regulate AI and to say AI is vastly more risky than the situation in North Korea. In past comments, Musk has likened AI development to “summoning the demon” and called it an existential threat.

His heavy criticism of the development has led him into arguments with Facebook CEO Mark Zuckerberg, an avid AI enthusiast. Several AI experts have also denounced Musk’s comments.

AI a “national concern”

Almost all the leaders on the global stage have started to invest in research and development of AI for national means, in some way. The Chinese government recently said it wants to be a leader in AI by 2030 and will invest heavily in companies working on the technology.

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Musk recently added his name to alongside 100 others asking for the United Nations to actively regulate autonomous weapons development, before it is deployed on the battlefield.

Even with all the criticism, Musk has founded an AI research firm, called OpenAI. The startup recently showed its technical prowess in the online strategy game DoTA 2. Musk has also founded Neuralink, which is reportedly developing brain-computer interfaces.